Various methods are known for routing network packets. For example, U.S. Pat. No. 4,939,726 entitled “Method for routing packets in a packet communication network,” which is incorporated by this reference, describes forwarding packets from a source node to a target node via a series of intermediates using the target node's geographic coordinates. Each intermediate node selects a successor node using, among other things, the maximum forward geographic progress attainable, which is determined by calculating a metric incorporating the geographical distance between the coordinates of the target node and the coordinates of each potential successor node. Similarly, U.S. Pat. No. 5,636,216, entitled “Method for translating IP addresses to other distributed network addressing schemes,” which is incorporated by this reference, describes using a network specific local address of a target node that incorporates the target's geographic coordinates.
Some networks are configured to determine and use radio nodes with latitude and longitude coordinates, which are shared amongst the radios of the network, for example, as radios discover one another. A radio uses the coordinate information about its neighbors to independently determine how to best route each packet based on the packet's final destination, for example by attempting to determine to which of the neighbors a packet should be sent in order to move it closest to the final destination. FIG. 1 illustrates one such exemplary network 10 comprised of various radios 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23. For illustrative purposes, the ranges of radios A-D 15, 16, 17, 18 are illustrated by circles 31, 32, 33, 34, respectively. When a packet originates at radio A 15 that is destined for radio D 18, an algorithm considers the radios 12, 13, 14, 16 within radio A's range 31 and selects radio B 16 because it is the closest to the destination D 18. Once the packet arrives at radio B 16, an algorithm considers the available alternatives and selects radio C 17 because it is physically closest to the destination D 18. Once the packet arrives at C 17, the destination is directly reachable. While these techniques offer many advantages, especially when radio range patterns are relatively circular 204 about a radio 202 as shown in FIG. 2a, with radio range extending approximately the same distance in all directions, various problems arise when one or more radio nodes in a network have different range patterns such as asymmetrical patterns 208a-c about a radio 206 as shown in FIG. 2b. For example, such patterns may occur when a radio is under glass or otherwise obstructed within a utility meter.